The disclosure relates to de-icing. More particularly, the disclosure relates to de-icing of turbomachines.
Icing of aircraft external rotating components during adverse ambient flight conditions is a well-known aerodynamic problem. A cutaway of a modern advanced twin spool turbofan engine is shown in FIG. 1. The large cone-shaped hub 70 (“spinner”; although known as a “nose cone” or “inlet cone” it is rarely actually conical but, instead typically has a longitudinally convex profile diverging rearward) at the base of the fan blades 34 is one particular area subject to icing.
Many anti-ice approaches have been developed in the past including both on-ground treatments and in-flight anti-icing. Some of the most widely used methods for de-icing the nose cone are either based on electrical resistive heating or using hot pressurized air bleed from a predetermined compressor stage of the engine. Resistive heating requires complex wiring, control logic, and current draw. Bleed heating involves a direct parasitic loss adversely affecting the thermodynamic performance of the engine and is, hence, undesirable.
In separate fields, permanent magnet arrays have been used in magnetic motors and generators. They have also been used in mechanical couplings. One proposed coupling is seen in U.S. patent application Ser. No. 13/344,697, filed Jan. 6, 2012, and entitled “Magnetically Coupled Contra-Rotating Propulsion Stages”. However, these are not configured to keep an exposed surface de-iced.